1. Technical Field
The present invention relates to a method of preparing an electrophotographic developer outside of an image developer, in which a powder such as a toner and a carrier which are constituents of the developer are mixed. In addition, the present invention relates to an electrophotographic developer prepared by the method, and a process cartridge and an image forming apparatus using the electrophotographic developer.
2. Description of the Related Art
In electrophotographic image forming apparatuses used in copiers, printers, facsimiles, etc., a developer has an important part to play in finally visualizing an image. A dry two-component developer in the current mainstream include magnetic particles called a carrier and resin particles including a colorant, which is called a toner.
The two-component developer preferably includes a toner at a uniform concentration. Therefore, in the process of preparing a developer contained in an image developer before use (hereinafter referred to as an “initial developer”), it is required to uniformly mix a toner and a carrier.
Japanese published unexamined applications Nos. JP-2008-020795-A and JP-2001-125317-A disclose a mixing process using a mixer rotating a mixing container a toner and a carrier are fed in. Japanese published unexamined application No. JP-H07-281482-A discloses a mixing process using a mixer rotating a stirring blade located in a mixing container a toner and a carrier are fed in.
The mixers disclosed in Japanese published unexamined applications Nos. JP-2008-020795-A, JP-2001-125317-A and JP-H07-281482-A need increasing the rotational number or time of the container and the stirring blade to more uniformly mix a toner and a carrier. To increase the rotational number or time needs increasing power of a drive source or drive time, resulting in increase of consumption energy of the drive source, i.e., increase of energy required to prepare a developer.
A powder mixed with a carrier in preparing a developer is not limited to a toner. The same problems could occur when a powder such as inorganic oxidized particles besides a toner and a carrier are uniformly mixed.
The initial developer has been explained. A developer for supply, called a “premix toner” including a toner more than the initial developer, increasing a concentration of a toner of a developer in an image developer when fed therein, and feeding a new carrier therein could have the same problem.
Because of these reasons, a need exist for a method of preparing a developer, which is capable of saving energy required in the process of mixing a powder and a carrier.